Question about AR15 Drop in Autoshears

leeblackman

I saw an advertisement in shotgun news for a preban drop in autoshear for an AR-15 for $225, thats supposed to be legal to put in to any AR15. Apparently it actually goes inside your reciever, not a cheap trigger attachment. They are not supposed to make them anymore too.My question is, how do they work?Do you have to take them out to make you gun shoot semi-auto again. The add said it will make you AR selective fire, but didn't give specifics.All opinions and any information on drop in auto shears would be highly appreciated.

cpermd

They act like the autosear in the M16.You need to use the M16 bolt and fire control parts.It is illegal to own one of those DIAS and an AR15.There are legal registered DIAS but they cost over $2500 and do work.Maybe your grandmother needs one but she better not have an AR.

JudgeColt

The part about which you are inquiring is called an "auto sear," not an "auto shear." I have not seen one for maybe 20 years, when it was not uncommon to see them at gun shows.The older AR-15 rifles had an open space behind the hammer and trigger where the auto sear in the M16 pivots. (The later semi-automatic rifles are "pinned and blocked," which amounts to a block being pinned with a blind pin into the space behind the hammer and trigger to prevent using the drop-in auto sear about which you inquire. Being that the block is pinned with a blind pin, it would be very difficult to remove the pin and thereby the block.)The "drop-in auto sear" device is a piece of aluminum or steel shaped to fit in the proper spot in the lower receiver. The aluminum or steel base is a carrier for a trip lever designed to fulfill the same purpose as the auto sear in the M16. The device is shaped so that it is held in place by the rear upper receiver boss through which the rear takedown pin travels to hold the upper and lower receivers together.The ATF issued rules making the drop-in auto sears made after a certain date subject to the same rules as NFA firearms, which means registration and a transfer tax. Additional rules were later promulgated to make having certain M16 parts in certain combinations subject to the same rules. I do not think that mere possession of a "pre-ban" auto sear with no other necessary parts constitutes a violation of the law. I think that is how those made before the cutoff date can still be legally sold. However, that is just my opinion and I caution you not to rely on it. Do your own research if you decide to buy one. Look at a picture of an M16 and you will see a pin above the selector near the top of the lower receiver. This is the pin on which the M16 auto sear pivots. The drop-in auto sear puts its trip in the same position and fulfills the same purpose when used with a M16 bolt carrier, hammer, trigger, selector and disconnector. The drop-in auto sear by itself does nothing without the M16 parts. (There was also a device designed to fill in the missing area in earlier AR-15 bolt carriers necessary to activate the trip as the bolt closed.)I have not looked at the advertisements for these devices for years, but, as I recall, they contained a picture of the device, which, coupled with my description, should give you a good idea how they work. I am told they worked, but some were poorly made and failed quickly. Hope this helps you understand this device. If not, I will try some more.

Boomerang

Don't listen to these guys. Go ahead and buy it. It must be legal, it was in Shotgun News for God sake. What a great buy, if they have alot of them, go ahead and buy them too and make a whole lot of money. No way the BATF would be trying to entrap you.BTW, I have a bridge for sale in Brooklyn, really. This is all legal and you can put toll booths on it to recoup all your money and be really, really rich one day.Boomer, I believe everything I read!

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Protect our Constitutional Rights.

boeboe

Those ads in shotgun news make no claim that they are legal to put in your AR. They are legal to own, but not if you own an AR. Like these guys say, you can't own one and an AR at the same time. Better read that ad again.

thunderbolt

"If it sounds too good to be true, it probably is, and not worth doing the time for the crime." Repeat those words to yourself every time you feel tempted to buyanything of questionable legality concerning guns.

leeblackman

Thanks Judge Colt, you've answered my questions 100% over. Don't think I haven't noticed your reply's in other posts, you really know your stuff, are you a gunsmith, or just a really smart person who loves guns, or both.Also thanks the rest of you guys, though my free spirited self says get one, I think I'm just going to wait and get a registered transferable Colt M16 lower reciever, and put all the stuff of my Colt on it. Then turn my AR into a match gun, its a good project for the later future.

JudgeColt

Mr. Blackman:No one has ever accused me of being smart before. Thank you! I wish it were true. I wish I lived in a state that allowed full-auto firearms, although I would probably be in the poorhouse after spending the price of a nice used car on dozens of desirable pieces. I am just a hobbiest who has been around guns all my life, and I have tried most, messed with many and owned quite a few. I am given to tinkering and altering, usually successfully. My father-in-law was a tool and die maker and I picked up a few machine skills from him, and some equipment. I cannot do reboring or rerifling, but I can do many less challenging things. Hand tools are usually all that are necessary to do most jobs.What I attempt is usually changing a stock gun in some way that I wish the factory had done. For instance, I have altered my beloved Colt Pony Pocketlite to make it even smaller and lighter. I did not like the excessively long tang, so I cut it off. I thought the muzzle was too sharp on the edges, so I beveled it back. I took off all the sharp edges. I drilled it full of holes in hidden places, including in the slide, to make it lighter. I have cut and lightened several slides and have always been afraid of upsetting the force balance and destroying reliability, but that has not happened yet with the relatively small amount of metal I have actually removed. I can tell on my Commander I cut to Detonics size that the lightened slide has a lot higher velocity than it had before I lightened it. If I shot it thousands of rounds, I suspect something would fail, but that is not its purpose.One of my more ambitious projects was converting a Remington M742 .30-06 to .300 Winchester Magnum. (I do not like the Browning Bar with its silly magazine arrangement.) The conversion works fine, but the magazine situation is not perfect. If I drop the altered magazine, it may (will usually) disgorge its cartridges. Box magazines are one of the toughest things to alter effectively. The Remington magazine is just too small for Magnum-size cartridges, even with the magazine body expanded to remove all the original indentations and taper. The magazine only holds two cartridges reliably, but three shots of .300 Magnum is not too shabby. Now if I could just get it rebored to .375....Anyway, thank you for the compliment. When I see people asking for gunsmith assitance on simple things, I wonder why they do not do it themselves, thus learning more about their firearm, plus getting further enjoyment out of their hobby, and receiving the satisfaction of having done it themselves. Try it everyone, you might like it!